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What is the distance for 25G SFP?
Knowledge Base + 2024.01.05

The distance for a 25G SFP (Small Form-factor Pluggable) module can vary depending on the specific model and specifications. However, in general, a 25G SFP module can support distances of up to 10 kilometers over single-mode fiber and up to 100 meters over multi-mode fiber. It's important to consult the manufacturer's documentation for the specific distance capabilities of a particular 25G SFP module.

1、Q:What are the types of 25G SFP28 optical modules?

A: There are three types of 25G modules, namely: 25G dual-fiber bidirectional module (SR, LR, ER), 25G single-fiber bidirectional module (BIDI), 25G WDM color optical module (CWDM, DWDM, LWDM).

2、Q:What is the longest transmission distance of 25G module?

A: At present, theoretically the farthest transmission distance can be realized 40KM.

3、Q:Can SFP28 optical module support backward compatibility?

A: It can support backward compatible 10G rate.

4、Q:Can SFP28 ports be interconnected with QSFP28 ports?

A: Yes, it can be interconnected, which can be realized by using module + patch cord or branch cable.

Module + Patchcord: Use 25G SR module for 25G end and 100G SR4 module for 100G end, and use multimode MTP/MPO-4xLC harness branch cable in the middle to connect.

Branch cable: use 100G to 4x25G breakout AOC/DAC cable to interconnect.

5、Q:Can 25G SFP28 ports support 10G modules?

A: Generally, the 25G port of the device can support multiple rates, such as 1G/10G/25G, in which the port can meet the use of 1G, 10G, 25G three rate modules.

6、Q:What is the farthest transmission distance of 25G DAC and AOC?

A: The farthest transmission distance of DAC is 5m, and the farthest transmission distance of AOC can reach 100m.

7、Q:Do I need to turn on FEC when using 25G module?

A: FEC can reduce the BER (bit error rate) of the module to 10-12, for 25G module, turn on RS-FEC when the current FEC BER is higher than 5×10-5, and turn on FC-FEC when the current FEC BER is higher than 10-8, for more details, please refer to Clause 74 of IEEE802.3 FC-FEC and Clause 91 of RS-FEC.

8、Q:Does the device need to enable FEC function when using 25G DAC?

A: According to the IEEE 802.3by protocol specification, 25G DAC does not need to turn on the FEC when the transmission distance is 1, 2 or 3m; when the transmission distance is 5m, it needs to turn on the RS-FEC.

9、Q:What is 25G dual-rate module?

A: Dual-rate is to support two types of rate, 25G dual-rate module can support 10G and 25G two types of rate, in the supported equipment port can be rate switching.

10、Q:What are the application scenarios of different types of 25G optical modules?

A: 25G SFP28 conventional optical modules (SR, LR, ER and BIDI) are mainly used for interconnecting servers, switches and routers in data centers.

25G CWDM SFP28 optical module is a single-mode duplex CWDM module, with a maximum rate of up to 25.78125Gbps, and a transmission distance of up to 40km through single-mode fiber, which is mainly applied to 25G Ethernet switches, routers, Network Interface Cards (NICs), and storage network equipment, and is capable of solving the problem of 5G millimeter-wave forward propagation well at the current stage;

25G DWDM SFP28 optical module is mainly used to meet the needs of 5G forward transmission service, the device adopts EML+APD scheme, the maximum rate is up to 25.78125Gbps, and the transmission distance can reach up to 10km through the single-mode optical fiber, which is widely used in the 25G Ethernet and single-mode SMF on the CPRI/eCPRI link, in which the wavelengths are tightly packed together to increase the bandwidth of existing fiber networks.

25G LWDM SFP28 optical module adopts high-performance and low-cost DML laser to provide 12-wave multiplexing, which is more advantageous than other similar 25G pre-transmission products in 5G pre-transmission applications. It makes up for the problems of large dispersion of 25G CWDM module and high cost of 25G DWDM optical SFP module laser, and saves 5G pre-transmission transmission while ensuring stable transmission, and thus is a stable and high cost-effective product in 5G pre-transmission network. network is a stable and cost-effective solution.